Telomeres are specialized structures found at the end of eukaryotic chromosomes. They have an important role in genome stability and cell growth by protecting chromosome ends from unwanted DNA metabolic activities. A variety of proteins are involved in this protective structure including telomere binding proteins as well as DNA repair proteins. Previous studies have shown that telomere chromatin isolated from mammalian cells have both a nucleosomal and non-nucleosomal component. Understanding the exact nature of telomere chromatin structure is essential for understanding its function. We plan to use an in vitro chromatin reconstitution approach to study the role of telomeric DNA, the G-strand overhang, telomere binding proteins, and histones in telomere higher-order structure. This will be achieved through the use of a quantitative agarose gel electrophoretic technique to determine the biophysical characteristics of telomere higher order structure. In addition we will use a telomere recruitment assay to identify telomere binding proteins, and histone modification states of reconstituted telomere chromatin. [unreadable] [unreadable]